This medication is used to treat anemia (low red blood cell count) in people with long-term serious kidney disease (chronic kidney disease). It works by signaling the bone marrow to make more red blood cells. Methoxy polyethylene glycol-epoetin beta helps to reverse anemia. It also helps to reduce the need for blood transfusions. This medication is very similar to the natural substance in your body (erythropoietin) that prevents anemia.